void GLSprite::generateVertices()
{
releaseVertices();
_vertices = new float[_coordinatesNumber * _pointsNumber];
float midWidth = _textureRectangle.size().w / 2;
float midHeight = _textureRectangle.size().h / 2;
float minX = - midWidth;
float minY = - midHeight;
float maxX = midWidth;
float maxY = midHeight;
_vertices[0] = minX;
_vertices[1] = maxY;
_vertices[2] = maxX;
_vertices[3] = maxY;
_vertices[4] = minX;
_vertices[5] = minY;
_vertices[6] = maxX;
_vertices[7] = minY;
}
/**
* \brief drawText, render 2D text on the screen (Orthogonal Projection)
* @param str, text string.
* @param pos, 2D position on screen,
* @param rgba, text color
* @param tick time elapsed
* @return float width of text string.
*/
float RenderText::drawText(const char*str, glm::vec3 &pos, glm::vec4 &rgba, float tick)
{
// checkGLError("RenderText::DrawText Should be ok!");
float width = 0;
mOPos = glm::vec3(0.0f,0.0f,0.0f);
mOPos = pos;
int num = strlen(str);
glm::vec4 *vertices = 0;
glDisable(GL_DEPTH_TEST);
glm::mat4 m = glm::ortho(0.0f, static_cast<float>(mWidth),static_cast<float>(mHeight),0.0f,-200.0f,1000.0f);
// Use the font class to build the vertex array from the sentence text and sentence draw location.
// Create the vertex array.
mScaleY = -mScaleY;
vertices = getVertices(str, false, &width); // note uses m_pos creates or retrieves existing vertex buffer from a cache table
mScaleY = -mScaleY;
TextShader &shader= mTextShader;
glEnable (GL_BLEND);
mBlendType = BL_ADDITIVE;
switch (mBlendType)
{
case BL_ADDITIVE: // Additive
glBlendFunc(GL_ONE, GL_ONE);
// glBlendFunc( GL_DST_ALPHA, GL_ONE_MINUS_SRC_COLOR ); // very good additive
break;
case BL_TRANSLUCENT: // Requires alpha
glBlendFunc(GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR);
// glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // Texture uses alpha
break;
case BL_SUBTRACTIVE:
//glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_COLOR);
glBlendFunc( GL_DST_COLOR, GL_ONE_MINUS_SRC_ALPHA ); //subtractive black => max
// glBlendFunc(GL_ZERO, GL_SRC_ALPHA); // needs alpha
// glBlendFunc(GL_ZERO, GL_SRC_COLOR);
break;
case BL_TRANSPARENT:
glBlendFunc(GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR);
break;
}
// Use the program object
glUseProgram(shader.mShader);
checkGLError("RenderText::DrawText glUseProgram (Text)");
// 1. create buffers tri array for simplicity? so that every tri can be handled separately or with a new index buffer could be expensive though???
// Load the vertex data
glVertexAttribPointer(shader.mAttribVtxLoc, 4, GL_FLOAT, GL_FALSE, sizeof(float)*4, &vertices[0].x);
checkGLError("RenderText::DrawText glVertexAttribPointer (V)");
glEnableVertexAttribArray(shader.mAttribVtxLoc);
checkGLError("RenderText::DrawText glEnableVertexAttribArray (V)");
glActiveTexture(GL_TEXTURE0 + 0);
checkGLError("RenderText::DrawText glActiveTexture");
glBindTexture(GL_TEXTURE_2D, mFont->GetTexture(0));
checkGLError("glBindTexture");
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
checkGLError("glTexParameteri");
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
checkGLError("glTexParameteri");
glUniform1i(shader.mTexture, 0 ); // Texture Unit 0
checkGLError("RenderText::DrawText glUniform1i");
// Once per frame
glUniform1f(shader.mTimeLoc, tick);
checkGLError("RenderText::DrawText glUniform1f");
glUniform2f(shader.mResolutionLoc, 1.0f/(float)mWidth, 1.0f/(float)mHeight);
checkGLError("RenderText::DrawText glUniform2f");
glUniformMatrix4fv(shader.mMatrixPVW, 1, GL_FALSE, &m[0][0]);
checkGLError("RenderText::DrawText glUniformMatrix4fv");
glm::vec3 sv(1.0f, 1.0f, 1.0f);
glUniform3fv(shader.mScaleV,1, (float *)&sv.x); // mScale location => variable "ScaleV" in vertex shader
checkGLError("RenderText::DrawText glUniformMatrix3fv");
glm::vec4 color = rgba;
glUniform4fv(shader.mColor,1, (float *)&color.x);
checkGLError("RenderText::DrawText glUniformMatrix4fv");
glm::vec4 TPos(mPos.x,mPos.y,mPos.z, 1.0f);
glUniform4fv(shader.mTPos, 1, (float *)&TPos.x);
checkGLError("RenderText::DrawText glUniformMatrix4fv");
glDrawArrays(GL_TRIANGLES, 0, 6*num);
checkGLError("RenderText::DrawText glDrawArrays");
// Clean-up
glDisableVertexAttribArray(shader.mAttribVtxLoc);
checkGLError("RenderText::DrawText glDisableVertexAttribArray (Vtx)");
glBindTexture(GL_TEXTURE_2D, 0);
glUseProgram(0);
checkGLError("RenderText::DrawText glUseProgram(0)");
releaseVertices(vertices, false);
glDisable(GL_BLEND);
return width; // Generate a buffer for the vertices
}
